A friend of mine in considering the purchase of a used Burton single, with
most of the original parts.  This was probably kit built in the late
'70's.  He asked me to have a look at it, and I was struck by how strong
the plectra are.  Is this typical of the Burton instruments, or is it
aging of the plastic in the tongue?  I would also appreciate any pointers
to printed information about  the Burton instruments, how they should be
maintained, if there is currently a supplier of parts for the
Burton instruments, and anything else which the wisdom of the list can
give me.
 
I appreciate any replies I receive, and thank you all in advance.
 
Deryck Harnett